tracing/fastboot: fix len of func buffer

Impact: fix possible stack overrun

This is a port of a patch included in the mainline (KSYM_SYMBOL_LEN fixes).
The current func len is not large enough to contain the max symbol len, the
right size must be KSYM_SYMBOL_LEN.
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

include/trace/boot.h

@@ -9,7 +9,7 @@
  */
 struct boot_trace_call {
 	pid_t			caller;
-	char			func[KSYM_NAME_LEN];
+	char			func[KSYM_SYMBOL_LEN];
 };
 
 /*
@@ -17,7 +17,7 @@ struct boot_trace_call {
  * while it returns.
  */
 struct boot_trace_ret {
-	char			func[KSYM_NAME_LEN];
+	char			func[KSYM_SYMBOL_LEN];
 	int				result;
 	unsigned long long	duration;		/* nsecs */
 };